Stimulating specific brain areas can cause monkeys to carry out complex behaviors, showing that such behaviors are hardwired into the primate mind.

While lower organisms such as insects are known to have largely hardwired behaviors, primates tend to mostly learn their behaviour. This lead to the assumption that most complex commands were not hardwired.

Researchers from Vanderbilt University in Nashville, Tennessee now report eliciting complex behaviors such as hand-to-mouth movements simply by stimulating specific areas in the brain of a small nocturnal primate called the Galago, providing support for the theory that all primate brains?including human?contain innate complex behaviors.

"We have now seen this feature in the brain of an Old World monkey and New World prosimian," says research head Jon Kaas. "The fact that it appears in the brains of two such divergent primates suggests that this form of organization evolved very early in the development of primates. That, in turn, suggests that it is characteristic of all primate brains, including the human brain."